Question

Help me factor?

Answer 1

\[3x ^{2}+31x+36\]

Answer 2

(Using the X method please)

Answer 3

never heard of the X method

Answer 4

the way i'd do it is

3 * 36 = 108

now find 2 factors of 108 which add up to 31

Answer 5

what do you think the 2 factors are?

Answer 6

I thought it was 27 and 4 but the correct answer is \[(3x+4)(x+9)\]

Answer 7

What I don't understand is how to get that answer

Answer 8

3x^2 + 31x + 36

= 3x^2 + 27x + 4x + 36
this can be factored by grouping

= 3x(x + 9) + 4(x + 9)

= (3x + 4)(x + 9

Answer 9

last line should be

(3x + 4)(x + 9)

Answer 10

follow that ok?

Answer 11

Thanks!